Phase difference pixels of a phase difference method (pupil division method) may be formed on an image sensor such as, for example, a CCD type or a CMOS type image sensor (solid-state image pickup element) such that the distance to a subject can be measured using the detected signal of the phase difference pixels. As a result, a high speed auto-focus can be achieved. Further, it becomes also possible to produce a stereoscopic image of the subject based on a subject image captured with the phase difference pixels.
As for a phase difference pixel which performs the pupil division of the phase difference method, phase difference pixels described in, for example, Patent Literatures 1 and 2 are known. The phase difference pixel of Patent Literature 1 is configured such that one microlens is provided for a plurality of adjacent pixels. The phase difference pixel of Patent Literature 2 is configured such that a portion of each microlens provided for each pixel is covered by a light shielding film. In some cases, a phase difference pixel may be formed by reducing an opening of a light shielding film of each pixel to be eccentric rather than providing a microlens.